The use of polyacrylamide solutions to treat hydrocarbon-bearing formations to reduce the water produced therefrom is well known. Arendt, U.S. Pat. No. 3,087,543, teaches to treat the entire production interval with an acrylamide carboxylic acid copolymer. Sandiford, U.S. Pat. No. 3,308,885, teaches to perform similar treatments employing a polyacrylamide solution wherein the polymer is from about 8 to about 70 percent hydrolyzed.
A method has now been discovered for improving the effectiveness of such treatments. The improvements consist in decreasing the water/oil ratio and increasing the time over which the treatment is effective.